^94 MR. F. E. BEDDARD ON THE [June 16, 



Partly in consequence of this the hyoirl musculature of Rhino- 

 derma is closely like that of Emm, the omohyoid being present, 

 which muscle has disappeared in Bi-eviceps. On the other hand, 

 the musculature of the floor of the mouth is quite specialised in 

 Rhinoderma, and different from that of any other frog the 

 anatomy of which has been described. 



On the other hand, there are a few points in which Rhinoderma 

 'does resemble Breviceps and departs so far fi-om the structure of 

 Rana. The sternohyoid seems to be a double muscle in both, 

 though the duplicity of the muscle is not so strongly marked in 

 Rhinoderma. The attachment and general appearance of the ilio- 

 lumbaris of Rhinoderma is distinctly like that of Breviceps. In 

 both, the rectus interims minor of the thigh arises partly from the 

 skin, and in neither frog is there the dorsal part of the depressor 

 mandibulae muscle present. In my paper upon Breviceps I have 

 selected 17 characters of importance to distinguish that frog from 

 Rana. It is only in four of these charactei'S that Rhinoderma 

 agrees with Breviceps to differ from Rana. 



Nor are there any special points of likeness between the two 

 genera here considered in an 3^ other features not mentioned in the 

 list of the seventeen principal characters refei'red to, excejDt, of 

 course, such general features as both Rhinoderma and Brevicep)s 

 share with Rana. 



The divergences are most remarkable ; and yet there are at 

 least two equally remarkable points of resemblance, i. e. the origin 

 of the rectus internus femoris anrl the absence of the dorsal part 

 of the depressor mandibulae. There can be no doubt, however, 

 that, whatever may be the value of these points of resemblance, 

 the two genera are quite as far removed from each other within 

 the limits of family relationship as diversity of geographical 

 position would lead us to expect. A wider knowledge of this 

 order of animals may reveal surer bases for anatomical criteria, 



6. Some Notes upon the Anatomy of CJdromys madagascari- 

 ensis, with references to other Lemurs. By Fkank E. 

 Beddard, M.A., F.E.S., F.Z.S. 



[Received May 26, 1908.] 



(Text-figures 150-153.) 



The opportiHiity of examining three specimens of the Aye- Aye 

 {Chiromys madagascariensis) has enabled me to add a few new 

 facts to what is already known concerning the structure of this 

 remarkable Lemur. The three principal Memoirs dealing with 

 the structure of Chiromys are (in order of appearance) those of 

 Owen*, Peters t, and Oudemans$. These authors have dealt 

 with the preceding literature relating to the animal. The 



* Trans. Zool. Soc. vol. v. f Abliandl. k. Akad. Wiss. Berlin, 1865. 



X Verb. Akad. Amst. 1890. See also Chapman, R Ac. Philad. 1900, p. 419. 



